Let-off means for strand or sheet material



March 24, 1959 G. E. CLENTIMACK 2,873,839

LET-OFF MEANS FOR STRAND OR SHEET MATERIAL Filed April 11, 1957 r 4 Sheets-Sheet 1 r i 45 INVENTOR.

Geone: ECLENTIMACK A TTORNE Y March 1959 G; E. CLENTIMACK 2,878,839

LET-OFF MEANS FOR STRAND OR SHEET MATERIAL Filed April 11, 1957 4 Sheets-Sheet 2 INVENTOR. Gzorzez E. CLENTIMACK A T TORNE Y March 24, 1959 G. E. CLENTIMACK 2,878,839

LET-OFF MEANS F OR STRAND QR SHEET MATERIAL Filed April 11, 1957 4 Sheets-Shee t 4 ill!!! I 14 Ella I :15} I g 7 I I INVENTOR.

Gzoasz E.CLENTIMACK A TTORNE Y United States Patent F 2,878,839 LET-OFF MEANS FOR STRAND 0R SHEET MATERIAL George E. Clentimack, North Attleboro, Mass., assignor to Draper Corporation, Hopedale, Mass., a corporation of Maine Application April 11, 1957, Serial No. 652,288 12 Claims. (Cl. 139-110) This invention pertains to means for letting ofi warp or other threads or other sheet material from beams or the like in machinery such, for example, as textile machines, and particularly to control of the let-off means and its function so as to deliver the warp threads or other sheet material uniformly under a prescribed condition.

It is a general object of the invention to devise a control means for textile or other machine let-offs which shall be very sensitive and adapted to compensate for variations in the tension of warp or other threads or of sheet material of any nature being let 01f thereby to maintain a very uniform condition in the material as it is advanced and further, to render more uniform the final product which may be affected by the condition under which the said material is let off or fed from a beam or other means.

A further object is that of providing control for such a let-off means which shall be sensitively and promptly adjustable for all changes in tension which tend to be permanent, but which will merely absorb without affecting the let-off means, all periodic variations which tend to be recurrent, that is, non-permanent, and further, to accomplish this by a simple mechanism inexpensive to manufacture and also, one which shall be relatively free from trouble and require very little upkeep or replacement over a relatively extended period of use.

A more specific object is that of devising such let-off means and control therefor which shall function through a speed reducing unit including a diflerential the differential drive gears of which are rotated oppositely and at differential speeds, the output torque of said differential being conveyed through to rotate the beam or other means on which the threads or sheet material is wound at a prescribed rate taking care of the reduction in diameter of the working beam as the material is exhausted, and also of all tension variations which occur for various reasons during the letting off of the material.

It is a further object to accomplish the above mentioned desired results by control of the differential speed reducing and regulating means by taking an indication from the tension in the material itself and by varying the diflierential speeds of the drive gears of the unit, increasing the speed of one as the speed of the other is decreased and vice versa.

Other objects will be apparent from the following more detailed disclosure.

In various types of textile machinery such as knitting machines, looms and the like, and in other similar equipment, warp or similar threads wound on a beam or beams and sheet material, either a fabric, paper or other material, are fed or let off from the beam at a rate dependent upon that at which they are required to be advanced for purposes of forming a fabric as they are combined or interlaced with other threads, or as the material is utilized or treated in some other fashion. Usually these beams are advanced by a let-off or drive means the speed of which must be varied to compensate for decrease in diameter of the supply on the beam and also for maintaining a uniform tension condition in the threads or other material.

Various devices have been used and these function well 2,878,839 cg Patented Mar. 24, 1959 in many instances, although it is still desirable to let off such material under still greater uniformity and within closer limits as to tension conditions. As the diameter of the beam decreases, compensation must be effective to speed up its rotation so that linear speed of the material and tension therein shall vary as little as is practically possible. Along with this function, most fabric forming and many other machines operate according to a cycle within which the warp threads are non-uniformly incorporated into a fabric,.that is, tend to be demanded more rapidly at one part of the cycle than anothenand thus set up periodic variations in tension. Since most control is taken from tension bars, whip rolls or the like which bear upon the warp threads at some point between the beam and fabric forming instruments, or other point at which the material fed from the beam is utilized, these variations are imparted to the control means along with other changes in condition which are or would be per; manent if not compensated. Reference will be made herein to periodic variation and to changes of permanent nature.

According to the invention, means is provided to control a variable speed drive means forming a part of a reduction train the input side of which is rotated at a uniform and prescribed speed due to being driven from some constantly and uniformly rotating source. The

1 sheet material in the event paper, fabric or such material is being handled, and the variable speed means thus controlled is adapted to be momentarily speeded up, retarded, and also to have its speed uniformly and slowly increased over the period of time required for drawing or feeding from the beam material the diameter of which may be considerable at the start, but decrease to a relatively small roll at the finish. This linkage from the sensing means to the variable speed means forms subject matter of copending application Serial No. 517,293, filed June 22, 1955, now Patent No. 2,792,023 and need not be described in great detail here, but includes a member presenting considerable resistance to rapid displacement due to its inertia and other means functioning on that which is resilient and which offers little or no frictional resistance to its movement.

The invention also contemplates a novel form of variable speed drive means incorporated in the entire train as an intermediate part thereof and comprises a differential the differential drive gears of which are oppositely rotated at differential speeds, that is, one being rotated faster than the other so long as actual advancing of the material from the beam is contemplated. This differential also includes one or more differential drive pinions, sometimes referred to as spider gears, which are rotated by the said drive gears and are also carried around bodily thereby to impart motions through their spider to which they are attached for rotation and for bodily movement therewith, for conveying the driving torque through to the output side of the train. Each of the gears oppositely driven is rotated through a common member which imparts its driving force preferably in a frictional manner, but the effective driving radius of which is adapted to be varied in minute increments so that the differential speed of the two drive gears may be increased or decreased, the opposite effect being evident on one gear as compared to the other, thereby to vary the output from the pinions through the spiderto the output side of the unit.

The invention will be described in greater detail by reference to specific embodiments thereof as illustrated in the accompanying figures of drawing, wherein:

Fig. 1 is a side elevation of a loom to which the invention has been applied.

Fig. 2 is a similar view ofa warp knitting machine.

Fig. 3 is a section showing one form of the let-off and considerable of the' mechanism employed therein.

Fig. 4 is a partial section showing other parts not evident in Fig. 3.

Fig. 5 is a plan view showing certain of the control mechanism.

Fig. 6 is a section showing a modification and control and reduction gearing involved therein.

Fig. 7 is a plan view similar to Fig. 5 but showing a modification.

Fig. 8 is a partial section showing certain of the details of Fig. 6 as seen from a different viewpoint.

Fig. 9 is a partial section showing a modification.

Now referring to Fig. 1, a loom to which the invention has been applied comprises, among other parts, a loomside 20, a crank shaft 21 and cam shaft 22. At the back of the loom a beam 23 is supported in bearings 24 in a conventional manner and has wound thereon a plurality of warp threads W which pass through the usual warp stop motion and harnesses (not shown) and are interlaced withtweft or filling threads to form a fabric. These latter parts and functions are not illustrated since they are well known.

The warp beam has atfixed at one side a gear 25 meshing with a pinion (not shown) fixed on a shaft 27 at the other end of which a worm gear 23 is in mesh with and driven by a worm 29. The latter pinion is keyed to the output shaft of the let-off drive means to be described in greater detail hereinafter and which is, according to the examples herein given by way of illustration, vertically disposed, although it is to be understood that in certain instances, the let-off mechanism which is or may be entirely enclosed is capable of being operated in other positions.

The drive unit may more correctly be stated to comprise an enclosed unit and the worm reduction which drives through the pinion to gear 25 as stated and which need not be considered a part of the drive or speed reducing and controlling unit itself and which is mounted within a bracket 30 attached by any suitable means to the loomside and upon which the drive unit may very conveniently be supported.

. This drive unit has at its input side a sprocket 31 keyed to a shaft 32 and a chain 33 is adapted to transmit power to the unit from any convenient rotating part of the loom. Here such drive is taken from the crank shaft 21 to which is fixed a larger sprocket 34. A tensioning sprocket 35 serves to keep the chain taut.

As the warp threads W are drawn off the beam, they arepassed about a whip roll 36 or other tension responsive means. Here roll 36 is rotatable in arms 37 pivoted at 38 in a bracket carried by extensions 39 of the loomsides. Suitable mechanism, for example as shown in US. Patent 2,535,515 or other equivalent devices, are applied at one or both sides of the whip roll pivot means so as to bias the arms and thus the whip roll in a direction to tension the warp sheet as it passes thereover. These whip roll tensioning means are well known and need not be shown or described in detail here. They are adjustable and may be controlled to put more or less tension on the warp and, of course, permit the arms to swing about that pivot so that the whip roll may be drawn downwardly or may in turn move upwardly against the tension of the warp sheet thus indicating the tension conditions therein and acting as a tension responsive indicator from which control may be taken as will hereinafter he described in detail for the purposes of governing the let-off speed change meansthereby to advance the warpthreads as required under as nearly uniform tension conditions as is practicable.

The whip roll functions in a known manner under-influence of the warp and its'positional variations are transmitted to the let-off unit by means such as that described in copending application Serial No. 517,293. Such means comprises an arm 40 fixed to the shaft or spindle 38 and having attached thereto a-spring arm 41 the position of which may be adjusted within limits by means of the adjusting screw 42 passed through the arm 40 and locked in position by any suitable locking means. This spring arm 41 connects at 43 to an offset depending link 44 the lower end of which is attached to certain controlling means at the let-off unit itself hereinafter to be described.

Now referring to Fig. 2, a warp knitting machine having more or less the usual construction includes a frame 45, warp beam brackets 46 and warp threads drawn from beams 47 and 48. These warp threads are passed over tension bars 49 and 50 on arms 51 and 52 pivoted at 53 and 54 on brackets 55 and are spring urged in an upward or clockwise direction to maintain tension on the threads as they are fed to needles at a knitting point at 56.

Both beams are driven to let off warp material by the units 57 and 58 similar to that shown in Fig. 1. These are controlled from the tension bars by linkage including resilient arms 59 and 60 and links 61 and 62. These arms are similar to the arm 43, Fig. 1.

While two textile machines which may employ to advantage the let-off and control means are herein described and claimed, these are given by way of examples only and the invention applies to all such machines or others in which there are similar problems of feeding warp threads as they are consumed during a fabric forming process, or of feeding or letting off other strip or sheet material of similar nature.

Now referring to Figs. 3 and 4, the let-off units are preferably of a reduction gear type in which between an input side and an output side there is provided a speed change mechanism. Power is taken in at the shaft 32 rotatable in bearings 63 and 64 supported in a part of a casing 65 and of a cap 66 bolted to the casing. This input shaft continuously and uniformly rotated as described has fixed for rotation therewith a friction disk 67. This disk 67 is splined to be driven by the correspondingly splined end 68 of shaft 32 thereby being slidable thereon and spring urged by the coil spring 69 into engagement with two disks 7t! and 71 fixed to hubs 72 and 73 rotatable on needle or other hearings on a shaft 74. This shaft 74 is shouldered having a washer 75 hearing against the shoulder and limiting the end movement of the hub 72 in that direction while at the opposite end Of this unit which will hereinafter be termed as a differential drive unit, is locked a washer 76, the two hubs being spaced apart by another hub 77 which has projecting stud or spindle 78 forming something of a spider on which is rotatable a differential drive pinion 79 being mounted on suitable antifriction bearings if desired and, of course, the number of these pinions may be increased to two, three or more depending upon the driving characteristics and requirements of the unit itself. The pinion is meshed with two differential drive gears numbered 80 and 81., the gear 80 being suitably keyed or otherwise attached to hub 72 while the gear 81 is likewise fixed to hub 73.

Thus it can be seen that the disk 79, hub 72 and gear 80 form one driving unit adapted to be frictionally driven by its contact with the disk 67, and at the other side a similar unit is likewise driven by said disk, while the differential drive gears meshing with the pinion 79 rotate that pinion since the two driving units rotate in opposite directions, but in the event the friction disks 7t and 71 are set at different radial distances from the center of the disk 67, will also carry the differential pinion and hub 77 around bodily or in a circular orbit thereby to rotate the shaft 74 since the hub is suitably keyed to that shaft. T he entire unit mounted on the shaft 74 is movable endwise as will hereinafter be explained and, depending upon its axial position and thus the radial distance of each disk 70 and 71 from the center of the disk 67, the differential speeds of the units by which the pinion 79 is rotated and carried around bodily may be varied within limits so as to take care of the rotational requirements incidental to feeding material from a full beam to an empty beam.

Shaft 74 also has a worm 82 keyed thereto which in turn meshes with the worm wheel 83 on a second shaft more clearly shown in Fig. 4. The worm is retained in place by means of a spacer or sleeve 85 which is interposed between the inner race of an antifriction bearing 86 of a type adapted to take both radial and thrust loads and maintained in place by snap rings, one at the end of the shaft and the other in the connterbored end of a bell-shaped member 87 slidable in a sleeve type bearing 88 bolted into the end of the casing and having a key and keyway pin as at 89 by means of which the member 87 is prevented from rotation but permitted to slide freely for the purpose of moving the shaft '74 and all parts maintained thereon lengthwise throughout such extent as is necessary to give the required amount of speed differential for the intended purpose. The opposite end 90 of the shaft 74 is mounted within an antifriction hearing which is also supported and slidable within a bore in the end plate 91, a part which serves both to seal the end of the casing and also to provide a bearing support for that end of the shaft. The counterbore in end plate 91 is of sufiicient depth to provide for the amount of end movement required for the shaft.

The worm wheel 83 is freely mounted upon shaft 92 which is rotatable in bearings 93 and 94. A turneddoWn shaft end 95 is slidably keyed in a sleeve 96, the key 97 being fixed in the shaft end, but slidable in .a keyway in the sleeve. Sleeve 96 is freely rotatable in a bearing in the cover 98 and has fixed externally of the casing a belt sheave 99 and a handwheel (not shown).

Driving engagement between the worm wheel 83 and shaft 92 is accomplished through a dog clutch 100 carried by a flange 101 on the end of sleeve 96 and forming a part of the wheel hub 102. A spring 103 normally maintain the clutch engaged, but if desired, the sleeve 96 may be pulled outwardly of the casing by the handwheel to disengage the clutch whereupon the handwheel may be employed to turn the shaft 92, the drive back through the worm, etc., then being disconnected.

Of course, the shaft 92 may attach for driving directly a beam or other core, or may, as in the case of the loom herein shown, drive through further reduction gearing including other worm, spiral and/or spur gearing.

The change of drive ratio at the differential is accomplished through a shaft 104, an end of which is threaded into the bell-shaped member 87. This shaft carries a collar 105 seated against a shoulder in a cap 106 and held in place by a snap ring or the like. It rotates in and is further restrained by a bearing 107 and has keyed to it a hub 108 to which are fixed two ratchet wheels 109 and 110, one for clockwise and the other for counterclockwise rotation.

A pawl carrying arm 111 is oscillatable on bearing 112 and is reciprocated by a link 113 pivoted at 114 on a smaller sheave 115. The latter is bent driven from sheave 99 by a belt 116. Pawls 117 and 118 are pivoted at 119 on arm 111 and are pressed by springs (not shown) to engage the teeth of their appropriate ratchet wheels except when held out of engagement therewith by a shield 120 adjustably fixed to an inertia member or fly wheel 121. This latter is freely rotatable on bearings 122 and 123 on shaft 104 and is connected by a link '44 or other means, to an arm such as arm 41 by which the flywheel and shield may be moved to uncover the appropriate ratchet wheel so that its ratchet may turn the wheel and shaft 104 to pull out or push in the shaft 74 as required to slow down or increase the differential output speed and thus change the rate of delivery.

By using a spring arm 41 and inertia member 121, the

6 brief effect of periodic variations is not conveyed through to the pawls so no speed change is efiected, but for changes of a permanent nature as when the beam is slowly diminished in size, the shield will be moved aside and one or the other of the pawls will then become effective to alter the differential output, either by way of increase or decrease of speed, as may be required to correct and to feed or let off the material under a tension of prescribed value.

A handwheel 124 serves to set the speed manually, for example, at the start of the function with full beam or package.

Now referring to Figs. 5, 6 and 8, a modification using a spur gear reduction and driving the oscillating pawl carrier from the internal mechanism will be described. A casing 125 has a cover 126 and cover plate 126. Power input to a shaft 127 drives at a uniform speed a friction disk 128. A differential generally indicated by numeral 129 and a substantial duplicate of that above described in detail is carried by shaft 130 slidable lengthwise in a bearing 131 in the bushing 132 and is controlled by a member 133 having a threaded stern 134 and sliding in a bore in an internal extension 135 of the cover 126. The end 136 of shaft 130 is rotatable in but axially movable with the member 133 being restrained by a bearing 137 similar to that before described at 86.

The shaft 130 rotated at a speed dependent upon the output of the differential drives an output shaft 138. This latter is carried in a bearing 139 and bushing 140 and is driven through a spur gear train comprising a pinion 141 fixed to shaft 130, idler 142 freely rotatable on a stud shaft 143, gear 144 and a second pinion 145 pinned to the shouldered end 146 of a shaft 147, and then gear 148 meshing with pinion 145, a third pinion 149 and finally, gear 150 keyed to shaft 138, Figs. 6 and 8. The pinion 145 is cut at the lower end of a sleeve rotatable on bearings on the upper, reduced end 151 of shaft 138 and both the hub of gear 144 and the sleeve of pinion 145 are pinned to end 146 of shaft 147 which terminates as shown just above the reduced end 151 of shaft 138.

Gear 148 is keyed to an extended hub of pinion 149 and both turn on bearings on stud shaft 152 being held by a snap ring or the like. Of course, stud shafts 143 and 152 are locked in bosses in the casing.

Returning to Fig. 6, an eccentric 153 carrying a bearing 154 of antifriction type, preferably, and having an elongated hub 155 is freely rotatable on shaft 147 and also in casing cover 126. A handwheel 156 is pinned to the shaft end and drives the eccentric by a pin 157 which, when the parts are in the position of Fig. 6, engages in a slot 158 in the wheel hub. The eccentric is held down by a snap ring 159, or the like, so that to rotate the parts by hand the handwheel may be raised freeing the eccentric drive and lifting gear 144 from mesh with idler 142. Then pinion 145, with teeth longer than the teeth of gear 144 or the movement of the part as described will still be rotated by the handwheel and shaft 147, and will turn shaft 138 directly through the remainder of the train. The gearing from input shaft 127 to idler 142 will be inactive and, of course, that permits the hand operation to be accomplished with little resistance.

Shaft 130 may move endwise as provided and the length of pinion 141 is such as to permit that while still being in mesh with idler 142.

Control is taken from eccentric 153 to a pawl carrier 160 pivoted on hearing 161 at the hub 162 within which the screw 134 is threaded. This hub has a shoulder 163 by which it is retained against endwise motion in one direction in the cover 126 and a washer to limit motion in the other direction. Pawls 164 and 165 engage ratchet wheels 166 and 167 keyed to hub 162 as shown. A link 168 threaded into eccentric strap 169 and connected to the arm or carrier 160 oscillates the pawls which, depending on the position of a shield 170;, ratchet theparts in one or the other direction to position shaft 130. Shield 170 is carried by an inertia member 171 similar to that at 7 121,.Figs. 3 and 4, and which is positioned by a link 172 connected to a'control arm 173 or the like which moves in accordance with the condition of a strand or web of material being fed or advanced as governed by the means herein described.

This arm 173 is clamped to one end of a short shaft 174 passing through bearing 175 and having fixed at its other end an arm 176 more or less at right angles to arm 173. A spring 177 tends to keep the parts in a neutral position as it pulls on one end of arm 176. A link or the like may be connected at 178 to the other end of the arm and such a link may then extend to a spring arm or the like at a whip roll or other tension member.

The mechanism just described is shown in certain other details in Fig. 9, this illustrating particularly the input shaft, disk and a spring of different type which may be applied to any of these devices. The disk 67 of Fig. 3 is pressed into engagement with its cooperating friction members by a simple coil spring, but in some instances it may be preferable to use a Belleville washer or spring 179 instead. Here the disk 128 is splined to slide on the shaft end and the washer provides the needed pressure.

The invention has been described by reference to more or less specific examples of let-off means which are applicable particularly to textile machines, however the use to which the device is put and the material involved are not to be limited to any particular class of machine or material so long as it is of a sort to be advanced in feeding from a supply in roll form and under substantially uniform rate and tension conditions.

While one embodiment and modifications of the inven tion have been disclosed, it is to be understood that the inventive concept may be carried out in a number of ways. This invention is, therefore, not to be limited to the precise details described, but is intended to embrace all variations and modifications thereof falling within the spirit of the invention and the scope of the claims.

I claim:

1. In a means for advancing and letting off material from a beam which includes a variable speed driving means having a member positively driven at a uniform speed at a power input side, a power output means and interconnecting drive means between said positively driven and output means which comprises a differential having oppositely rotating differential drive gears and a differential pinion, said pinion being rotated by said differential drive gears and further carried around bodily for imparting torque to said power output means, and shiftable means for rotating said differential drive gears at different speeds.

2. In a means for advancing and letting off material from a beam which includes a variable speed driving means having a member positively driven at a uniform speed at a power input side, a power output means and interconnecting drive means between said positively driven and output means which comprises a differential having oppositely rotating differential drive gears and a differential pinion, said pinion being rotated by said differential drive gears and further carried around bodily for imparting torque to said power output means, means for rotating said differential drive gears, one at a speed in excess of the other, and control means for increasing the speed of rotation for one gear and simultaneously decreasing it for the other.

3. In a textile machine the combination of cooperating devices for combining threads including warp threads, means for letting off said warp threads which includes a variable speed driving means having a member positively driven at a uniform speed at a power input side, a power output means and interconnecting drive means between said positively driven and output means which comprises a differential having oppositely rotating differential drive gears and a differential pinion, said pinion being rotated by said differential drive gears and further carried around bodily for imparting torque to said powertoutput means,

and shiftable means for rotating said differential drive gears at different speeds.

4. In a textile machine the combination of cooperating devices for combining threads including Warp threads, means for letting off said warp threads which includes a variable speed driving means having a member positively driven at a uniform speed at a power input side, a power output means and interconnecting drive means between said positively driven and output means which comprises a differential having oppositely rotating differential drive gears and a differential pinion, said pinion being rotated by said differential drive gears and further carried around bodily for imparting torque to said power output means, means for rotating said differential drive gears, one at a speed in excess of the other, and control means for increasing the speed of rotation for one gear and simultaneously decreasing it for the other.

5. In a textile machine the combination of cooperating devices for combining threads including warp threads, means for letting off said warp threads which includes a variable speed driving means having a member positively driven at a uniform speed at a power input side, a power output means and interconnecting drive means between said positively driven and output means which comprises a differential having oppositely rotating differential drive gears and a differential pinion, said pinion being rotated by said differential drive gears and further carried around bodily for imparting torque to said power output means, means for rotating said differential drive gears which comprises a friction disk forming a part of said input means and other disks, one for each differential drive gear, in frictional contact with the disk first mentioned, and control means for simultaneously varying the effective radius of the points of contact between said disks at the differential drive gears.

6. Mechanism as defined in claim 5 wherein said means for varying the effective radius comprises devices for moving the differential and its disks parallel to the surface of said driving disk at the input means.

7. Mechanism as defined in claim 6 where said means for moving the differential and its disks as stated comprises an axially movable, threaded means controlled by selectively operable ratchet means.

8. In a textile machine the combination of cooperating devices for combining threads including warp threads, means for letting off said warp threads which includes a variable speed driving means having an input means including a shaft and a friction disk rotatable therewith, a second shaft perpendicularly disposed to said input shaft, a gear member fixed to said second shaft and forming a part of a train of gears for rotating an output member, said variable speed drive means further comprising a differential having drive gears and a pinion, a hub carrying said pinion and keyed to said second shaft, said differential drive gears being freely rotatably on said shaft, a friction disk fixed to each said drive gear and having frictional engagement with the disk first mentioned, and means for simultaneously varying the radial position of the said differential and friction disks thereat relatively to the disk at the input shaft.

9. Mechanism as defined in claim 8 wherein said gear member fixed to the second shaft is a worm and the train cooperating therewith includes a worm wheel.

10. Mechanism as defined in claim 8 wherein said gear member fixed to the second shaft is an elongated spur gear and the train cooperating therewith includes a multiple reduction spur gear system.

11. Mechanism as defined in claim 8 wherein said second shaft is movable endwise to vary the radial position of said disks.

12. Mechanism as defined in claim 8 wherein means is provided for disconnecting the drive beyond a point at the output side of said differential and for rotating the remainder of the mechanism manually.

No references cited. 

